Figure 4.

Grain characteristics and starch physicochemical characteristics in the ospk2 mutant. (a–d) The per cent contents of total starch, amylose, protein and lipid in endosperm of wild‐type (WT) and ospk2. (e) Differences in the amylopectin chain length distributions between the WT and ospk2. (f) Pasting properties of endosperm starch of WT (red line) and ospk2 mutant (blue line). The viscosity value at each temperature is the average of three replicates. The grey line indicates the temperature changes during the measurements. (g) The gel consistency of endosperm starch of WT and ospk2 mutant. (h) Gelatinization characteristics of starch in urea solutions. Starch powder of WT and ospk2 was mixed with varying concentrations (1–9 m) of urea solution. Asterisks indicate the starch of ospk2 endosperm is more difficult to gelatinize in 4–9 m urea solution than that of WT. The most significant difference was observed for 4 m urea (right panel). Values in (a–d, g) are means ± SD from three biological replicates. Asterisks indicate statistical significance between WT and mutant, as determined by a Student's t‐test (*P < 0.05; **P < 0.01).